Mercury switch relay



June 30, 1936. I Q Hl LARSON 2,046,273

MERCURY SWITCH RELAY Filed Oct. lO, 19554 3 Sheets-Sheet 1 @j J5 j@ 92 46' 7.14? i@ @6i ffl l l www n mi' nl Y www 35 26 @/QJZO?? @l/d Tenganv mwa June 30, 1936. C H LARSON 2,046,273

MERCURY SWI TCH RELAY Filed oct. 1o, 1935 v 3 sheets-sheet 2 c. H. v LARsoN 2,046,273

MERCURY SWI TCH RELAY June 30, 1936.

3 Sheets-Shana# 3 Filed 001;. l0, 1955 if hun ELU/enton- @Lila/5072, VS7

p Patented June 30, T936 MERCURY swr'rclr RELAY Carl H. Larson, Elkhart, Ind., assigner to The Adlake Company, a corporation of Illinois Application Dctober 1l), 1935, Serial No. 44,399

i 1i) Claims.

The primary object of this invention is to provide a compact, readily accessible, and reasonably inexpensive mounting for mercury switch relays oi the type in which a magnetically controlled plunger armature, moving in response to a relay coil, displaces more or less mercury within a switch envelope to change the condition of the electrical circuit through electrodes projecting into the envelope.

l0 Other objects are to provide a mounting which facilitates inspection and minor repairs, permits switch elements to be changed without dismantling the entire relay, excludes dirt and dust from 1 to the operating parts of the relay unit.

Further and other objects and advantages will become apparent as the disclosure proceeds and the description is read in conjunction with the accompanying drawings, in which Fig. 1 is a side, elevational view of a relay embodying my invention;

Fig. 2 is a front, elevational view of the same; Fig. 3 is a wiring diagram showing a circuit which may be used with the three coil unit shown ln the illustrative form of the invention;

Fig. 4 is a transverse, sectional view through the relay taken on the line 4 4 of Fig. 6;

Fig. 5 is a horizontal, sectional view taken on the line 5 5 of Fig. 4;

Fig. 6 is a vertical, longitudinal, sectional view taken on the line 6--6 of Fig. 5; and

Figs. 7, 8 and 9 are views corresponding to Figs. 4, 5 and 6, respectively, but showing a modiiled form of the invention.

It will be understood that the disclosure oi speciic embodiments of the invention are for the purpose of complying with Sec. 4888 of the revised statutes. and. the appended claims are to be construed as broadly as the prior art will permit.

The relay unit shown in the drawings is inm tended for shelf mounting. it comprises, in gen1 eral, a base lll, a sub-unit ll mounted on the base, and a cover le. The sub-unltconsists oi three vertical coil units i2, i3 and llheach oi 45 which includes a mercury switch of the type in which mercury is displaced by a magnetically controlled plunger to change the condition of the circuit through electrodes projecting into the switch envelope. This type oi switch, broadly, is

50 disclosed in Larson PatentNo. 1,957,951, issued July 24, 193i.

The base lil is preferably made of cast aluminum. and comprises side walls it and il, rear wall i8, front Wall i9 and top wall 2B, the latter 55 being reinforced by gussets 2l and 22 merging the relay unit, and prevents unauthorizedaccessY (Gl. 20G- 112) into the rear wall i8. The top wall 2li has a relatively large longitudinal opening 23 adjacent to its forward edge in order to receive the lower ends of the mercury switches associated with the coil units I2, i3 and lf3. 5

As will be seen by ref rrlng to Figs. d and 6 particularly, the base lll is hollow and is provided at its four corners with bosses 24 which are drilled and tapped to receive machine screws 25 which secure a base coverA plate 26 to the base. 10 Preferably. the plate 26 is lined with an insulator 2l to avoid any possibility of wires from the switches short circuiting through the cover.

The front portio-n of the base is inclined away from the main body of the relay and on this l5 inclined portion, a terminal block 28 of insulating material is adapted to be removably secured. The block is secured to the base by screws 29 two of l them entering tapped holes in the corner bosses 24 and the other two entering tapped holes in the other bosses 30. The block can, therefore, be easily removed for checking the wiring.

A plurality of terminal posts 3| are mounted on the terminal block 28, the heads 32 of the posts bearing against longitudinal ridges. 33 25 formed on the block in order to keep the posts from turning when thevbinding post nuts 34 are screwed into place.

The base is mounted on rubber feet 35 secured y to the base cover 26 by bolts and nuts 36. 30

The inclined terminal block has the advantage that it discourages careless workmen from laying tools on the posts and thereby short-circuiting'. the relay.

The sub-unit I! l comprises an L-shaped bracket 35 made of sheet steel andthe coil units l2,` i3 and it with their respective switchesfll, lil and land their respective coils t9, dil and 5l. Each` coil unit includes an iron magnetic circuit comprising a laminated yoke 52, thc legs `of which@ abut against the ends of the switch associatedwith the unit. Tube clips 53 attached to the ends ci the yoire embrace the switch and holdit within the coil subject to vertical adjustment by an adjusting device generally designated 56compris- 45 ing a rod t5 vertically movable within .aguide 5t attached to the yoke 52 and having its lower end extending through an opening 5l in the top wall 2li of 'the base l0. The end of the rod Stils bent laterally and drilled to receive a clip which y engages a `oaltelite sleeve iid sealed on to the lower end of the mercury switch. The upper end of the rod ed is threaded to receive .adjusting `nuts fill and a spring 5l is interposed between the guide Sil and the laterally extending portion of the rod 55 55 so as to always hold the switch in its adjusted position within the relay.

A bracket 62 is used to secure the vertical coil units to the lsuppcrt bracket 45. See Figs. 4 and 5, particularly.

In assembling the sub-unit il to the base Ill,

the switches 36, 31, 48 and the adjusting devices 54 are ilrst omitted from the sub-unit as= sembly and the latter is secured to the base with screws 63. The switches 46, 41 and 48 are then putin place and the adjusting rods 55 inserted upwardly through the openings 51 in the top wall of the base. The nuts 6l) are then screwed into place and the sub-unit is completely assembled on the base. lThe sub-unit is completely enclosed by the cover l5 which seats on a ledge 54 formed on the base, a cork or felt gasket being interposed between the cover and base to exclude dirt and dust. The cover has a large opening 55 in its iront face which receives a window t1 held in place by a retainer 68 secured to the cover by screws 69. |li'he window E1 exposes the entire iront portion of the sub-unit ll to view.

'Ihe cover l5 is secured to the base l0 by screws 18 which engage studs 1i rising from the base. The cover l5 is preferably provided with recesses( 12 where the screws 1li pass through the top Wall of the cover in order that the surrounding space may be lled with sealing compound to prevent unauthorized access to the interior of the relay In the form of the invention shown in Figs. 7-9 inclusive, the vertical coil units are similar to the ones shown in Hedin Patent No. 1,967,948 issued July 24, 1934, and the adjusting device, here designated 15, is alongside the switch 2. Each coil unit is secured to the support bracket by a pair of brackets 16, each of which is provided with a keyhole slot for attachment to the support bracket. Except for the above mentioned changes, the relay is substantially the same as shown in Figs. 4, 5 and 6.

gIn Fig. 3, a circuit is shown for a relay of the type herein disclosed. The purpose of the relay when used with this circuit is to transfer a load 11 from its normal source of power (alternating current) to a secondary source of power (direct current) when the former fails for any reason, and to transfer the load back to the primary source of power when it revives. The alternating current source of power is indicated at 18 and the direct current source at 19, and the former is connected to binding posts 80 and 8l, the latter to binding posts 82 and 83. The load 11 is connected to binding posts 84 and 85, and the remaining binding posts 86 and 81 are connected to the secondary o! theV transformer 88. The switch 41 is of the front contact type, i. e. the circuit through the switch is closed when the associated c oil is energized. This is indicated diagrammatically by the position of the plunger 89 (it being assumed that the coil 50 is energized).

The switches 46 and 48 each have three electrodes, one in contact at all times with the mercury and the other two only intermittently in contact with the mercury. The two intermittently immersed contactsare of different heights, the shorter being' withinthe plunger, land the longer being outside. The plunger 98 is closed at its top as indicated diagrammatically, and has a small opening di in its side wall just above the level of the mercury when the associated coils and 5I are energized. When the plunger is in this position, i. e. with the coils energized, the mercury in the switches covers the short electrodes and connects the load to the alternating current supply of power, but when this source ot power for any reason falls below a predetermined 5 value, the coil 50 is cie-energized and allows the plunger 89 to rise a suicient distance to break the circuit through the switch 41. This de-energizes the coils 49 and 5i causing their respective plungers 98 to fall by gravity to a lower position. As soon as the opening 9i reaches the mercury, the gas entrapped within the upper portion of the plunger forces the mercury away from the shorter electrode and simultaneously raises the mercury level on the outside, thus placing the load 11 in circuit with the battery 19 and disconnecting the mercury from the alternating current source 1B. When the current in the alternating current source is revived, the coil 5&3 pulls thtplunger B9 downwardly and thereby energizes 20 the relay coils d@ and 5l and again places the load in the circuit with the alternating current source.

I claimz- 1. In a mercury switch relay, a hollow base 25 having a top wall provided with an opening extending along its forward edge, a sub-unit mounted on the top wall comp'risingan Lbracket and a plurality of vertical coil units attached to the bracket, a mercury switch associated with each coil unit at least one of said switches projecting downwardly through the opening in the top wall of the base.

2. In a mercury switch relay, a hollow base having a top wall provided with an opening extending along its forward edge, a sub-unit mounted on the top wall comprising an L-bracket and a plurality of vertical coil units attached-to the bracket, a mercury switch associated with each unit at least one of said switches-:sprojcting downwardly through the opening in the top wall of the base, and -a switch adjusting device associated with the last-named switch.

3.V In a mercury switch relay, a hollow base having a top wall provided with an opening extending along its forward edge, a sub-unit mounted on the top wall comprising an L-bracket andl a plurality of vertical coil units attached to the bracket, a mercury switch associated with each unit at least one of said switches projecting downwardly through the opening in the top wall of the base, and a switch adjusting device associated with the last-named switch, said device including a rod vertically movable through an opening in the top wall of the base.

4. In a mercury switch relay, a hollow base having a top Wall provided with an opening extending along its forward edge, a sub-unit mounted on the top wall comprising an L-bracket and a plurality of vertical coil units attached to the bracket, a mercury switch associated with each coil unit at least one of said switches projecting downwardly through the opening in the top wall of the base, and a. removable cover on the base enclosing the sub-unit.

5. In a mercury switch relay, a hollow base having a top wall provided with an opening extending along its forward edge, a sub-unit mounted on the top wall comprising an L-bracket and a plurality of vertical coil units attached to the bracket, a mercury switch associated with each coil. unit at least one of said switches projecting downwardly through the opening in the top wall of the base, and a removable cover on the base enclosing the sub-unit, said cover havinga window in said forward wall exposing the sub-unit to view.

6. In a mercury switch relay, a hollow base having a top wall provided with an opening extending along its forward edge, a sub-unit mounted on the top wall comprising an L-bracket and a plurality of vertical coil units attached to the bracket, a mercury switch associated with each coil unit at least one of said switches projecting downwardly through the opening in the top wall of the base, a removable cover on the base enclosing the sub-unit, the relay base projecting beyond the forward face of the cover, and a terminal block carried by said projecting portion of the base.

7. In a mercury switch relay, a hollow base having a top wall provided with an opening ex tending along its forward edge, a sub-unit mounted on the top wall comprising an L-bracket and a plurality of vertical coil units attached to the bracket, a mercury switch associated with each unit at least one of said switches projecting downwardly through the opening in the top wall of the base, al switch adjusting device associated with the last-named switch, said device including a rod vertically movable through an opening in the top wall of the base, and a removable cover closing the bottom of the base.

8. In a mercury switch relay, a hollow base having a top wall provided with an opening extending along its forward edge,- a sub-unit mounted on the top wall comprising an L-bracket and a plurality of vertical coil. units attached to the bracket, a mercury switch associated with each unit at least one of said switches projecting downwardly through the opening in the top wall voi' the base, a switch adjusting device associated with the last-named switch, said device including a rod vertically movable through an opening ln the top wall of the base, a removable cover closing the bottom of the hase, and a plurality of feet carried by said cover.

9. In a mercury'switch relay, a hollow base having a top wall provided with an opening extending along its forward edge, a sub-unit mounted on the top wall comprising an L-bracket and a plurality of vertical coil units attached to the bracket, a. mercury switch associated with each coil unit at least one of said switches projecting downwardly through the opening in the top wall ofthe base, a removable cover on the base enclosing the sub-unit, the relay base projecting beyond the forward face of the cover, and a terminal block carried by said projecting portion of the base, said terminal block being inclined away from the main body of the base.

10. In a mercury switch relay, a hollow base having a top wall provided with an opening extending along its forward edge, a sub-unit mounted on the top wall comprising an L-bracket and a plurality of vertical coil units attached to the bracket, a mercury switch associated with each coil unit at least one of said switches projecting downwardly through the opening in the top wall of the base, a removable cover on the base enclosing the sub-unit, the relay base projecting beyond the forward face of the-cover, and a terminal block carried byA said projecting portion of the base, said terminal block being readily removable from the base.

CARL H. LARSON. 

